Screening module
A screening module 10 comprises a frame component 12 to be secured to an underlying screen deck, in use. A screening panel 14 is carried by the frame component 12. The screening panel 14 comprises an operatively upper screening surface 16 and a support structure 18 underlying the screening surface 16 with a plurality of spaced protrusions 20 being supported by and standing proud of the support structure 18. Operatively upper ends of the protrusions 20 lie substantially in a plane of the screening surface 16 and the protrusions 20 define a plurality of screening apertures 22 in the screening surface 16.
Latest Ludowici Australia Pty. Ltd. Patents:
The present application claims priority from Australian Provisional Patent Application No 2006900170 filed on 13 Jan. 2006, the contents of which are incorporated herein by reference.
FIELDThis invention relates generally to the screening of particulate materials and, more particularly, to a screening module and to a screening assembly including such a module.
BACKGROUNDIn the screening of particulate materials, such as ores, using screening modules there is a trade off between flexibility of a screening panel of the screening module, screening accuracy and open area of the screening module. There is a desire to have the screening panel reasonably flexible to inhibit blinding or pegging of screening apertures of the screening panel. However, if the screening panel is too flexible, there is a risk that oversized ore particles may pass through the apertures. This can have adverse consequences downstream of a screen deck comprising a plurality of the screening modules and may also give rise to penalties.
There is always the desire to have as great an open area as possible to allow the maximum throughput through the screen deck. The open area is generally understood to be the percentage of a surface of the screening panel of the module that is constituted by apertures. Once again, if there is too high a percentage of open area, i.e. a large percentage of the panel is constituted by apertures, there is a risk that the panel will be too flexible and oversized ore particles may pass through the apertures.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
SUMMARYAccording to the invention there is provided a screening module which comprises
a frame component to be secured to an underlying screen deck, in use; and
a screening panel carried by the frame component, the screening panel comprising an operatively upper screening surface and a support structure underlying the screening surface, with a plurality of spaced protrusions being supported by and standing proud of the support structure, operatively upper ends of the protrusions lying substantially in a plane of the screening surface and the protrusions defining a plurality of screening apertures in the screening surface.
The support structure may comprise a plurality of cross members. In one embodiment, the cross members may be arranged in a grid or lattice of intersecting cross members. The protrusions may be arranged on the cross members where the cross members intersect. In another embodiment, the cross members may be arranged in spaced parallel relationship. The cross members may extend in an in-flow direction of the module. In this embodiment, the protrusions may be arranged at spaced intervals on the cross members. The protrusions of adjacent cross members may be aligned with each other or, instead, the protrusions of adjacent cross members may be staggered with respect to each other.
If desired, each of at least certain of the cross members may be convex, or bowed, when viewed from a side of the cross member, to provide increasing stiffness towards a central region of the cross member.
Each protrusion may be in the form of a flat topped projection extending from the grid structure. Sides of each projection may taper inwardly from the top of the projection to a mounting position of the projection on the support structure. It will be appreciated that such tapering assists in inhibiting blinding of the screening apertures. It will further be appreciated that the support structure defines a plurality of openings, the openings underlying the screening apertures. However due to the tapered nature of the projections and the cross-sectional dimensions of the cross members, the openings are larger than the apertures. Thus, material passing through the apertures should pass with ease through the openings of the support structure.
The projections may have any suitable outline in plan. Thus, the projections may be rectangular (including square) in plan view. The projections may be arranged diagonally on their associated cross members. Instead, to increase the open area of the screening module further, the projections may be cruciform in plan view. The projections may be arranged on their associated cross members with arms of the cross-shaped projections extending diagonally relative to the cross members when viewed in plan.
The frame component and the screening panel may be integrally formed as a one-piece unit. The unit may be moulded from a suitable synthetic plastics material. The material may be polyurethane. At least the frame component may carry reinforcing to impart rigidity to the unit.
Instead, the frame component and the screening panel may be formed as two separate elements, the screening panel being removably attached to the frame component.
The module may be rectangular. At least the shorter sides of the module may carry mounting formations for securing the module to an underlying screen deck. The mounting formations may be clips carried on the shorter sides of the module, the clips engaging retention rails on the screen deck. Instead of the clips, the mounting formations of the screening module may be receiving formations in each of which a part of a retaining member, as described in International Patent Application No. PCT/AU2005/001376 entitled “A screening module retaining member” dated 9 Sep. 2005, or any modification thereof, is received.
The screening apertures may be arranged in a plurality of aperture arrays. Each aperture array may be delineated by a skirt portion underlying the screening surface. Each skirt portion may bound the support structure associated with that aperture array.
The invention extends also to a screening assembly including a screening module as described above.
In
The module 10 is a one-piece moulding of a suitable synthetic plastics material, more particularly, a polyurethane material. Typically, the polyurethane material has a Shore Hardness in the range from about 85 to 93 depending on the application of the module 10.
It will, however, be appreciated that, instead, the screening panel 14 could either be moulded separately from the frame component 12 and adhered to the frame component 12. Instead, the screening panel 14 could be releasably secured to the frame component 12 to be replaceable separately from the frame component 12. Thus, in the embodiment shown in
The screening panel 14 defines a screening surface 16. A support structure 18 (
The protrusions 20 define, between them, a plurality of screening apertures 22. As shown most clearly in
The apertures 22 are arranged in a plurality of discrete aperture arrays 24. In this embodiment, these aperture arrays 24 are formed by a central member 26 of the module 10 and a plurality of lateral members 28 extending at right angles from the central member 26. These members 26, together with sides 30 and 32 of the module 10, effectively define the aperture arrays 24. More particularly, each aperture array 24 comprises a skirt portion 34 (
In this embodiment, each support structure 18 is in the form of a lattice structure or grid 36. The grid 36 comprises a plurality of orthogonally arranged, intersecting cross-members 40 intersecting at points 38. A protrusion 20 is arranged on each intersecting point 38 of the grid 36.
Each protrusion 20 is in the form of a flat topped projection 42 terminating in the plane of the screening surface 16 of the screening panel 14 of the module 10.
Further, each projection 42 has inwardly tapering sides 44 tapering from its top towards it mounting point 38 on the grid 36. These tapering sides 44 inhibit blinding of the apertures 22 (in the case of wet screening of materials) or pegging (in the case of dry screening of materials).
The cross-members 40 of the grid 36 are of narrow cross-section. As a result, openings 46 (shown most clearly in
It is also to be noted that some projections 42 are formed integrally with the lateral members 28 or the side members 32, as the case may be.
As illustrated, the screening module 10 is substantially rectangular and the shorter sides 32 carry mounting formations in the form of clips 48 for clipping to retention rails (not shown) of an underlying screen deck (also not shown). Because the aperture arrays 24 are square and, therefore, symmetrical, the screening modules 10 can be arranged either with their shorter sides parallel to the direction of flow of material over the screen deck or at right angles to the direction of flow of material over the screen deck.
Referring now to
In this embodiment, the grid 36 of the support structure 18 has a coarser pitch than the grid 36 of the previous embodiment. By “coarser pitch” is meant that the openings 46 defined by the cross members 40 are of larger cross sectional area. Also, there are fewer mounting points for the projections 42. Thus, there are fewer projections 42 than in the previous embodiment. This therefore increases the size of the apertures 22 defined by the projections 42 and results in a screening panel 14 having an even higher open area than the preceding embodiment.
The cross members have a convex, or bowed, lower edge as shown most clearly in
It is also to be noted that, unlike the embodiment shown in
Referring to
In this embodiment, two different configurations of aperture arrays 50 and 52 are provided for illustrative purposes. A central part of the illustrated panel shows a conventional aperture array 54 not using the present invention. The aperture array 54 is illustrated for comparative purposes only and forms no part of the present invention.
In this embodiment of the invention, the support structure 18 comprises a support arrangement of spaced, parallel cross members 40. In other words, intersecting cross members are not included so that slot shaped openings 56 (
It is to be noted that the cross members 40 are arranged in an in-flow direction in the module 10, i.e. extending parallel to the direction of flow of material over the screening surface 16 of the screening module 10.
The projections 42 are arranged at spaced intervals along each cross member 40. In the case of the aperture array illustrated at 50 in
In
In this embodiment, instead of the projections 42 being square in plan view outline, the projections 42 are cruciform in shape having outwardly projecting arms 58. When viewed in plan, the arms 58 are diagonally arranged relative to the cross members 40 on which the projections are mounted. Thus a pair of projections 42 on one of the cross members 40 and a corresponding pair of projections 42 on an adjacent cross member 40 form rhombus-shaped apertures 22.
In the version shown in
End faces 60 of the arms 58 of the projections 42 are tapered to inhibit blinding or pegging.
The screening module 10 may, instead of being secured to the underlying rails using clips 48, be attached to the underlying rails using the Applicant's pin system as described in International Patent Application No. PCT/AU200S/01376 entitled “A screening module retaining member” or using one of the systems described in International Patent Application Nos. PCT/AUO2/01463 or PCT/AUO2/01668, both entitled “Screening panel securing system”.
In use, as the screen deck vibrates and material passes over the screening modules 10, materials having dimensions smaller than dimension ‘d’ pass through the apertures 22 and the openings 46 or 56 in the support structure 18. The tapered nature of the projections 42 inhibits blinding or pegging of the apertures 22 and facilitates passage of material through the screening module 10. A further advantage of this configuration of screening module 10 is that the projections 42, themselves, vibrate. In so doing, this assists in dislodging material.
As described above, there is a trade off between flexibility of the screening module 10, screening accuracy and open area of the screening module. Because the projections 42 protrude upwardly from the support structure 18, there is a greater open area defined. It will be appreciated that, because the support structure 18 sits at a level below the screening surface 16 of the module 10, it does not reduce the open area of the screening module 10. This substantially increases the open area of the screening module 10. The Applicant has calculated that, with a screening module in accordance with at least the first embodiment of the invention, due to the absence of cross and in-flow ligaments defining screening apertures, an aperture pattern having an open area exceeding 64% can be obtained. This compares extremely favourably with conventional aperture patterns (such as shown at 54 in
It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.
Claims
1. A screening module which comprises
- a frame component to be secured to an underlying screen deck, in use; and
- a screening panel carried by the frame component, the screening panel comprising an operatively upper screening surface and a support structure underlying the screening surface, with a plurality of spaced protrusions being supported by and standing proud of the support structure, operatively upper ends of the protrusions lying substantially in a plane of the screening surface and the protrusions defining a plurality of screening apertures in the screening surface.
2. The module of claim 1 in which the support structure comprises a plurality of cross members.
3. The module of claim 2 in which the cross members are arranged in a grid of intersecting cross members.
4. The module of claim 3 in which the protrusions are arranged on the cross members where the cross members intersect.
5. The module of claim 2 in which the cross members are arranged in spaced parallel relationship.
6. The module of claim 2 in which the protrusions are arranged at spaced intervals on the cross members.
7. The module of claim 6 in which the protrusions of adjacent cross members are aligned with each other.
8. The module of claim 6 in which the protrusions of adjacent cross members are staggered with respect to each other.
9. The module of claim 2 in which each of at least certain of the cross members are convex, or bowed, when viewed from a side of the cross member, to provide increasing stiffness towards a central region of the cross member.
10. The module of claim 1 in which each protrusion is in the form of a flat topped projection extending from the grid structure.
11. The module of claim 10 in which sides of each projection taper inwardly from the top of the projection to a mounting position of the projection on the support structure.
12. The module of claim 1 in which the frame component and the screening panel are integrally formed as a one-piece unit.
13. The module of claim 1 in which at least the frame component carries reinforcing.
14. The module of claim 1 in which the screening apertures are arranged in a plurality of aperture arrays.
15. The module of claim 14 in which each aperture array is delineated by a skirt portion underlying the screening surface.
16. The module of claim 15 in which each skirt portion bounds the support structure associated with that aperture array.
17. A screening assembly including a screening module as claimed in claim 1.
2870910 | January 1959 | Welmer |
4563270 | January 7, 1986 | Wolff |
4661245 | April 28, 1987 | Rutherford et al. |
4674251 | June 23, 1987 | Wolff |
4832834 | May 23, 1989 | Baird, Jr. |
5085324 | February 4, 1992 | Dehlen |
5462175 | October 31, 1995 | Bokor |
7090083 | August 15, 2006 | Russell et al. |
7303079 | December 4, 2007 | Reid-Robertson et al. |
51180 | May 1982 | EP |
Type: Grant
Filed: Jan 12, 2007
Date of Patent: Feb 14, 2012
Patent Publication Number: 20070175802
Assignee: Ludowici Australia Pty. Ltd. (Brisbane)
Inventors: Ronald Leslie Johnson (Warners Bay), Peter Martin Olsen (Roronto), Warren Anthony Spinks (Warners Bay)
Primary Examiner: Joseph C Rodriguez
Assistant Examiner: Kalyanavenkateshware Kumar
Attorney: Wong, Cabello, Lutsch, Rutherford & Brucculeri, L.L.P.
Application Number: 11/622,897
International Classification: B07B 1/49 (20060101);